I tripped and fell on the sidewalk on sunday. it looks like road rash on my knee. there's yellow crust, redness, it feels hot and there is a deep pain in the bones. i spray it with bactine 3 times a day. can there be infection without puss?

Yellow Crust: Yellow crust often represents a staph infection. I would have your doctor take a look.

Yes: Pain, redness and warmth can be signs of infection. You should be evaluated by a physician that can examine the wound.

See a doctor: Infection can occur without visible puss. Area will be red, hot, tender and swollen. Sounds like you should be examined by a professional immediately. Do not wait until this gets worse. Good luck and best wishes.